//The MIT License

//Copyright (c) 2009 Lluis Sanchez, Nick Darnell

//Permission is hereby granted, free of charge, to any person obtaining a copy
//of this software and associated documentation files (the "Software"), to deal
//in the Software without restriction, including without limitation the rights
//to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//copies of the Software, and to permit persons to whom the Software is
//furnished to do so, subject to the following conditions:

//The above copyright notice and this permission notice shall be included in
//all copies or substantial portions of the Software.

//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//THE SOFTWARE.

using System;
using System.Reflection;
using System.Reflection.Emit;
using Polymorph.Properties;

namespace Polymorph
{
    public class CodeNotEquals : CodeConditionExpression
    {
        CodeExpression exp1;
        CodeExpression exp2;
        Type t1;
        Type t2;

        public CodeNotEquals(CodeExpression exp1, CodeExpression exp2)
        {
            this.exp1 = exp1;
            this.exp2 = exp2;

            t1 = exp1.ResultType;
            t2 = exp2.ResultType;

            if (t1.IsValueType && t2.IsValueType)
            {
                if (t1 != t2)
                    throw new InvalidOperationException(Resources.CantCompareDiffPrimTypes);
            }
        }

        public override void Generate(ILGenerator gen)
        {
            if (t1.IsPrimitive)
            {
                exp1.Generate(gen);
                exp2.Generate(gen);
                gen.Emit(OpCodes.Ceq);
                gen.Emit(OpCodes.Ldc_I4_0);
                gen.Emit(OpCodes.Ceq);
            }
            else
            {
                exp1.Generate(gen);
                exp2.Generate(gen);
                gen.Emit(OpCodes.Ceq);

                gen.Emit(OpCodes.Ldc_I4_0);
                gen.Emit(OpCodes.Ceq);
            }
        }

        public override void GenerateForBranch(ILGenerator gen, Label label, bool branchCase)
        {
            if (t1.IsPrimitive)
            {
                exp1.Generate(gen);
                exp2.Generate(gen);
                if (branchCase)
                    gen.Emit(OpCodes.Bne_Un, label);
                else
                    gen.Emit(OpCodes.Beq, label);
            }
            else
            {
                exp1.Generate(gen);
                exp2.Generate(gen);

                gen.Emit(OpCodes.Ceq);
                gen.Emit(OpCodes.Ldc_I4_0);
                if (branchCase)
                    gen.Emit(OpCodes.Beq, label);
                else
                    gen.Emit(OpCodes.Bne_Un, label);
            }
        }

        public override void PrintCode(CodeWriter cp)
        {
            if (t1.IsPrimitive)
            {
                exp1.PrintCode(cp);
                cp.Write(" != ");
                exp2.PrintCode(cp);
            }
            else
            {
                cp.Write("!(");
                exp1.PrintCode(cp);
                cp.Write(".Equals (");
                exp2.PrintCode(cp);
                cp.Write("))");
            }
        }

        /// <summary>
        /// Gets the result type of the expression.
        /// </summary>
        public override Type ResultType
        {
            get { return typeof(bool); }
        }
    }
}